posted 30 Apr 2019, 08:15 by Peter Boggild
[
updated 30 Apr 2019, 08:15
]
Quantum Systems and Nanomaterials group, Physics Department, University of Exeter, UK.
The coexistence of semiconducting
properties and a stable oxide dielectric suitable for transistor applications
are some of the key aspects beyond the success of Silicon. The leap to future imperceptible,
wearable and flexible applications is now held back by the lack of mechanical
flexibility inherent to a Silicon wafer. The development of sensing and
computing on textile fibres(1) and biological tissues poses stringent constrains
on the mechanical properties of materials in addition to their optical and
electrical characteristics. The discovery of 2D semiconductors characterized by
an unprecedented combination of physical properties is enabling a wide range of
fundamental and applied science discoveries. However, the lack of a 2D system
with a mechanically flexible oxide suitable for transistor, memory, light
emitting and sensing devices has been holding back the true potential of these
novel systems. In this talk I will present the discovery of a mechanically
flexible and air stable high-k oxide obtained from the photo-oxidation of the
atomically thin semiconductor HfS2. Hence I will show how spatially controlled photo-oxidation
can be used to engineer specific strain patterns in a two-dimensional
semiconducting sheet, leading to an unprecedented tailoring of the energy
bandgap. I will discuss, how these strain fields can be used to generate
built-in electric fields necessary to observe inverse charge-funnelling(2) that
is the funnelling of photo-excited charges away from the excitation area
towards regions where they can be efficiently separated and collected. Finally
I will review the use of this novel mechanically flexible oxide in layered
transistors, memories, light emitting devices and photodetectors(3)[1] E. Torres et al., Nature
Flexible Electronics 2, 25 (2018)
[2] De Sanctis A. et al.,
Nature Communications 9, 1652 (2018)
[3] Peimyoo, N. et al., Science Advances 5,
eaau0906 (2019)
Saverio Russo is Associate Professor and
academic leader of the Quantum Systems and Nanomaterials group in the Physics
Department at the University of Exeter in the United Kingdom. Following a
master in Physics at the University of Pisa (Italy) and a master in Materials
Engineering from the Katholieke Universiteit Leuven (Belgium), he received the
PhD degree in Physics from the Kavli Institute of Nanoscience Delft in the
Netherlands in 2007 for pioneering studies on electron transport in hybrid
structures. He has joined the University of Exeter in 2010, after securing a
JSPS fellowship at the University of Tokyo (Japan). His research focusses on
fundamental and applied science of emerging quantum systems to include 2D
materials, and his scientific discoveries have regularly been featured by broad
audience media to include BBC, NBC, The Guardian, etc. |
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